Stars

Binary Star Systems

Does the Sun have a binary companion?

Although a binary companion to the Sun has never been detected, it is remotely possible that a very faint, very distant star could be orbiting the solar system at a great distance, similar to the way that Proxima Centauri (Alpha Centauri C) may be orbiting Alpha Centauri A and B. This idea has been explored in popular science fiction, and this tiny companion has been nicknamed Nemesis—the avenging goddess of justice in ancient Greek mythology, who was also called the Daughter of the Night. Some people hypothesize that such a companion might occasionally change the orbit of distant comets just enough that they might plunge in toward the center of our solar system and strike Earth. There is no scientific evidence to support these ideas, however.